Flow modules or reactors, which comprise plates stacked together and with plates manufactured in materials having large temperature expansion coefficient and low modulus of elasticity, operate over a wide temperature range. The large temperature expansion coefficient and low modulus of elasticity of the materials of the plates, compared to framework, screws, tension rods and end plates etc. can cause damages or leakage. Thus, one problem is to keep the tension over the whole construction within limits over the whole temperature range without causing leakage or damage on any of the parts in the module or reactor.
Another problem that occurs when working with plates is to distribute contact pressure as equal as possible over the plates to prevent unevenness and thus leakage or damaging any of the stacked plates.